[jcifs] questions about SmbTransport.getSmbSession

[Tapperson Kevin]

I have a few questions about SmbTransport.getSmbSession; maybe someone can answer them.

Here is a copy of the method for reference:
    synchronized SmbSession getSmbSession( NtlmPasswordAuthentication auth ) {
        SmbSession ssn;

        ListIterator iter = sessions.listIterator();
        while( iter.hasNext() ) {
            ssn = (SmbSession)iter.next();
            if( ssn.matches( auth )) {
                ssn.auth = auth;
                return ssn;
            }
        }

                                        /* close old sessions */
        long now = System.currentTimeMillis();
        if( sessionExpiration < now ) {
            sessionExpiration = now + SO_TIMEOUT;
            iter = sessions.listIterator();
            while( iter.hasNext() ) {
                ssn = (SmbSession)iter.next();
                if( ssn.expiration < now ) {
                    ssn.logoff( false );
                    iter.remove();
                }
            }
        }

        ssn = new SmbSession( address, port, localAddr, localPort, auth );
        ssn.transport = this;
        sessions.add( ssn );

        return ssn;
    }

1) Is there any reason that the sessions object in SmbTransport is a LinkedList?  I think it would make more sense to implement the sessions object as a Map (using an NtlmPasswordAuthentication object as the key).  This would provide constant time access to a matching SmbSession in the getSmbSession method rather than linear time as it is currently.  The first section of code above could be replaced as follows:
        ssn = (SmbSession)sessions.get( auth );
        if( ssn != null ) {
            ssn.auth = auth;
            return ssn;
        }

2) Why was SO_TIMEOUT chosen as the poll interval for the session expiration/cleanup code in SmbTransport.getSmbSession?  We have jcifs.smb.client.soTimeout set to 0 to avoid getting NT_STATUS_ACCESS_VIOLATION errors (see previous threads related to soTimeout).  I am concerned that because of this we are suffering a performance penalty in that our SmbSessions expire immediately on creation.  On our QA servers, we have seen an issue with our login functionality when there is a high degree of concurrency.  We are in the process of conducting further performance testing to isolate the problem.


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